# GHSA-x8jh-xj3x-gx3c: `fast-float` has multiple soundness issues

> Attackers can trigger undefined behavior and memory corruption in the unmaintained fast-float library, potentially leading to code execution or crashes.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Oct 2024
- **Also known as:** RUSTSEC-2024-0379

## What is GHSA-x8jh-xj3x-gx3c?

GHSA-x8jh-xj3x-gx3c is a memory corruption vulnerability in fast-float, published on 31 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

`fast-float` contains multiple soundness issues:

 1. [Undefined behavior when checking input length](https://github.com/aldanor/fast-float-rust/issues/28), which has been merged but no package [pubished](https://github.com/aldanor/fast-float-rust/issues/35).
 1. [Many functions marked as safe with non-local safety guarantees](https://github.com/aldanor/fast-float-rust/issues/37)

The library is also unmaintained.

## Alternatives

For quickly parsing floating-point numbers third-party crates are generally no longer needed. A fast float parsing algorithm by the author of `lexical` has been [merged](https://github.com/rust-lang/rust/pull/86761) into libcore. When requiring direct parsing from bytes and/or partial parsers, the [`fast-float2`](https://crates.io/crates/fast-float2) fork of `fast-float` containing these security patches and reduces overall usage of unsafe.

## Which versions are affected by GHSA-x8jh-xj3x-gx3c?

3 open source packages ship an affected version, including fast-float.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `fast-float` | crates.io | All versions to 0.2.0 | None |
| `fast-float` | crates.io | All versions to 0.2.0 | None |
| `fast-float` | crates.io | From 0.0.0-0 | None |

## How do I fix GHSA-x8jh-xj3x-gx3c?

No fix has been published for GHSA-x8jh-xj3x-gx3c yet. Limit exposure of the affected software until one is available.

## Is GHSA-x8jh-xj3x-gx3c being exploited?

There is no known exploitation of GHSA-x8jh-xj3x-gx3c in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-x8jh-xj3x-gx3c and fix it if it is affected.

What it is: GHSA-x8jh-xj3x-gx3c is a memory corruption vulnerability in fast-float, published on 31 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-x8jh-xj3x-gx3c in the wild and no public exploit code.

Affected packages and fixed versions:
- fast-float (crates.io): affected all versions up to 0.2.0; no fix listed
- fast-float (crates.io): affected all versions up to 0.2.0; no fix listed
- fast-float (crates.io): affected from 0.0.0-0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-x8jh-xj3x-gx3c/ (Markdown: https://insights.sbomify.com/GHSA-x8jh-xj3x-gx3c/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-x8jh-xj3x-gx3c

---
From sbomify Insights: https://insights.sbomify.com/GHSA-x8jh-xj3x-gx3c/
Summaries are generated and may contain mistakes; the official description above is the record.